I had the same problem and fixed it with help from Corsair support. I will attach the important reply from them and also further steps to make sure it works.
CORSAIR REPLY:
Reinstalling the firmware of your device may correct the issue. We suggest doing this manually, and have uploaded the firmware for your device to the ticket in order to do so. Please follow the directions below:
1: Unplug your mouse from the computer.
2: Locate the small pinhole underneath your mouse. For some, this will be located directly on the bottom in plain sight. On others, it will be located underneath one of the removable weights attached to the bottom of the mouse.
3: Using a small paperclip or push-pin, press down on the button inside the pinhole.
4: Plug your mouse back into the computer, while holding down the pinhole button.
5: Once it is plugged back in, your computer should recognize a drive called CRP_Disabled. Please open this.
6: Download the firmware file from the ticket. If it is compressed into a .RAR file, please extract this file to an easily found location on the computer.
7: Delete the file FIRMWARE.BIN from the CRP_DISABLED drive, and then place the file with ISP in it’s name to the CRP_Disabled drive.
8: Once you have performed the steps above, please unplug your mouse and then plug it back in. The device will then return to normal. Please test to see if the issue reappears. If it does, please inform us on the ticket for further troubleshooting.
I have the file if anyone needs it, just email me at bznicely@gmail.com
FURTHER STEPS:
I downgraded from iCUE 4.11.274 to iCUE 3.38.61, which was specified as the proper iCUE for the M55 RGB Pro on the Corsair downloads page and it seems like the problem has been fixed. I updated the mouse firmware to 4.7.23 once and restarted my PC and I didn’t have to update it again after reboot.
So it seems like iCUE 4 might have something weird going on with the M55.
UPDATE (06 - 06 - 2021):
Corsair Ticket assistants confirmed that iCUE 4 is not compatible with all Corsair products so just downgrade your software and that will help a lot of issues.
